Guides
Answers to the questions people actually ask, each with the matching free check built in so you see your own result as you read.
Why is my email going to spam?
Why receiving servers distrust some email, what SPF and DMARC do, and how to check your own domain now.
SSL certificate expired: what it means and how to fix it
What visitors see when a certificate expires, why certificates now expire more often, and how to check yours now.
My domain is about to expire: what happens and what to do
What stops working when a domain lapses, how the grace periods work, and how to check your expiry date now.
Website down? How to tell if it is DNS
How to tell whether a site is unreachable because of DNS, and which DNS problems stop visitors reaching it.